A multiple pin probe is a probe that includes multiple pins. A measurement technique commonly referred to as current in-plane tunneling, or CIPT, uses multiple pin probes to take measurements of magnetic tunnel junction resistance.
More specifically, current in-plane tunneling takes measurements in multiple measurement steps. Each measurement step commences by selecting four of the pins in a multiple pin probe. Two of the selected pins are coupled to current sources and the other two of the selected pins are coupled to voltage meters. Current is passed through the two current-carrying pins and voltage is measured through the two voltage-metering pins. This measurement step is then repeated multiple times (with different selection/coupling of four pins in each measurement step) to extract the magnetic tunnel junction resistance.
It is noted that the repetitive nature of the current in-plane tunneling measurement process means that the measurement steps are performed at different times. It also requires a relative long period of time to complete the measurement process (e.g., in eight or more measurement steps), during which the pins may change positions, leading to measurement variations and inaccuracies.